Its Chapter 11 filing is the third largest behind the telecommunications giant WorldCom and investment bank Lehman Brothers, whose collapse marked the current financial meltdown in September last year.

In many respects GM's filing isn't really news at all. It's been coming for months and months.

Last Friday, I was joking with a trader on the floor of the New York Stock Exchange that a reporter like me could "mail the story in". He meant, of course, that it's all so predictable.

This man stopped trading GM shares long ago, well before their closing value of less than a dollar.

Now, however, he is wondering who will replace GM in the top 30 countdown of famous companies known as the Dow Jones Industrial Average? He's got seven companies in mind - Cisco Systems, Apple, Google, Oracle, Monsanto, Wells Fargo and Goldman Sachs.

Incidentally, GM will be the first Dow component to lose its place in the "Hot 30" because of bankruptcy in more than three decades.

GM Europe

GM's European division - GM Europe - maker of brands like Vauxhall in the UK and Opel in Germany, will most likely stay out of the bankruptcy proceedings because on Friday the Canadian car-parts maker Magna agreed to buy GM Europe with the help of the German government.

Magna is backed by Russian money and has ambitions to expand into Russia.

It's still likely to lay off thousands of workers but probably far fewer than Fiat would have done if it had won the bidding.

What is Chapter 11?

Back on home turf in New York and Detroit, what happens now to GM?

President Obama will give full details at 14 GMT on Monday 1st of June.

Opel look likely to stay out of bankruptcy processdings after Magna's acquisition [AFP]

Chapter 11 Bankruptcy Protection is a device used by American business to reorganise themselves when things go badly wrong.

It buys them time, but is hugely embarrassing for the management team who look like complete failures.

A judge runs the company on a day-to-day basis making decisions on how every penny is spent.

For the time being, GM plants will go on making vehicles and workers will turn up for work to knock them out and be paid for it.

Though, clearly, a lot of pain must be expected among the workforce quite soon.

The Obama administration hopes that GM's bankruptcy filing will be swift allowing a slimmed-down version of the company to be back in business in about three months.

GM's Plan

Chapter 11 requires a firm to have a restructuring plan and GM's has been much in the news lately.

In GM's case it would be split into two separate companies. "Old GM" would have all the "bad" assets like the rundown car plants and brands like Pontiac, Hummer and Saturn in it, while "New GM" would contain all "good" bits like money-making car plants and popular brands like Chevrolet, Cadillac, GMC and Buick.

The company's bond holders rejected GM's first restructuring plan last week, walking away from an offer that would have given them a 10 per cent stake in the New GM in exchange for interest payments on the $27bn they have already sunk into the company.

Later an ad-hoc group of bond holders agreed to accept a reworked deal that would eventually give them roughly 25 per cent of the new firm.

However, not all bond holders agreed to the new deal and may yet decide to fight for their cash through the courts, which could slow the bankruptcy proceedings down a bit.

All creditors will have their say when the bankruptcy court convenes a special committee to look into all aspects of GM's debt probably by the end of the month.

Chrysler

Of course GM is not the only US car firm in bankruptcy protection right now.

GM's debt

GM's total liabilities of $185bn break down into:

$27bn in unsecured debt$25.5bn in government and bank loans$20bn owed on healthcare and pensions$112.5bn in other debt

It's rival, the third largest US vehicle maker Chrysler, is also being run by a judge.

Cynics would tell you that Chrysler's bankruptcy filing was designed to be a role model for the much larger GM's filing ... and it certainly looks as if things have been going pretty well for Chrysler with its sale to Fiat of Italy likely to be approved by a judge in New York on Monday June 1st.

If you think the timing of all this is a little suspicious ... it almost certainly is!

One contact of mine told me: "There are powerful people at work behind the scenes to make sure all this gets done."

Airlines

Not that bankruptcy protection works for everyone.

With notable exceptions such as Continental and US Airways, several airlines have used it as a tool in the past to help turn themselves around and look at how well they're doing now.

Famous American names like Pan-Am, Braniff and Eastern Airlines spring to mind. Hey wait a minute!